Pile response to lateral spreading of liquefied soils

Soil liquefaction has been a major cause of damage to pile foundations in many of the past earthquakes. Particularly damaging for piles have been excessive ground displacements caused by spreading of liquefied soils in sloping ground and in waterfront areas. The analysis of piles subjected to lateral spreading is burdened by the uncertainties associated with the spreading of liquefied soils. Namely, it is very difficult to reliably predict the magnitude and spatial distribution of post-liquefaction ground displacements as well as to estimate the stiffness and strength of the spreading soils. Thus, the key issue is how to deal with unknowns in the analysis while capturing the essential features of pile behaviour. From a practical viewpoint, we need rational analysis methods that permit us to assess the pile response by considering various lateral displacements and stiffness properties of spreading soils. This paper discusses efforts towards developing such an analysis methodology and addresses, (a) field performance and damage features of piles in the 1995 Kobe earthquake, (b) key parameters controlling the pile response to lateral spreading and (c) experimental findings from benchmark tests on full-size piles.